The #1 not ok thing is not being transparent in communication around sexual issues. It is IMO, why communication and talking has to be done before intimacy is engaged.
From a guy POV, not all guys can afford the $500 for a small supply of ED medicines, which for quite a few health insurance providers are only given if you have heart conditions.
What some women may not realize are the side effects from the pills can be pretty horrible. Picture getting a boner with a migraine ....
What a guy can do is make sure their blood pressure and cardio health is good, they fit in the frame work of decent weight and BMI, and manage their health. If they are not doing so, then maybe they should not step up to "ride the ride" until they are ready.
If a man is transparent, understand that it strikes at a level of vulnerability where some women may understand intimately, but their bodies don't show it.
I can tell you what was worse then the rape I had? Having an ex-girlfriend call me gay after an ED hit a week after my rape. I shared it with her and the damage that was done "was horrible". It fucked me up massively. Now most guys don't have that experience, but looking down and saying WTF ... is probably one of the most disappointing and hard things that a man in our modern messed up society feels.
But I digress ...
What I have learned is some women need badly penetration, and others prefer oral. No two women are the same (hence the need to talk a lot).
But for women that fall into the camp of needing and desiring penetration as they age, it is a perverse kind of hell. The pool of men that fit the category fall like a rock given bad health practices.
Then they get to experience a thirst equal to teenage boys in a reverse WTF-ism where I am horny but have no one to f*ck. It is a hell most men can empathize with very very well.
Good luck and good hunting!